A doorbell is typically configured as a signaling device placed near a door to a building's entrance that, when activated, alerts an occupant to the presence of a visitor. Doorbells have existed for over 200 years with early versions using mechanical actuators (e.g., pull cords) to strike a bell plate, and later commercially available models (circa 1900) using electrical systems with chimes, bells, or buzzers. Conventional electrically controlled doorbell systems with mechanical chimes have changed little over the years and still exist in many households today.
There have been many technological advances in doorbell systems since their inception. For instance, some doorbell systems may incorporate wireless technology. For example, the doorbell button may contain a battery-powered radio transmitter that sends button state data (e.g., on or off) to a receiver that triggers a chime. Some chimes may be digitally implemented using a sound chip that plays the sound of a bell through a speaker. Some contemporary systems may incorporate a video camera to provide the user with a visual confirmation of the visitor.
Despite the many advances, many contemporary systems that enhance existing doorbell implementations (e.g., adding video capability) need cumbersome add-on supplementary circuitry that is often subject to significant power constraints and limited functionality, require trained technicians to test existing systems and properly install the add-on circuitry, and often require significant doorbell system overhauls that can be costly. Better doorbell system designs are needed.